The present disclosure is directed generally to bleed valves, and more specifically, to a shaft seal assembly for butterfly bleed valves.
Butterfly valves include a valve element (e.g., disc) mounted onto a rotatable shaft extending through a flow path through the valve. When the valve element occupies a closed position, contaminants (e.g., dust, sand particles, foreign objects, etc.) can build-up and fall into a bearing compartment at an end of the rotatable shaft. Operation of bearings (e.g., roller bearings and/or ball bearings) in the bearing compartment can be impaired and/or damaged by these contaminants which can degrade performance of the bearings and possibly result in eventual failure of the butterfly valve.